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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/pickle.h"
#include "mozilla/Alignment.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/EndianUtils.h"
#include "mozilla/Telemetry.h"
#include "mozilla/ipc/ProtocolUtils.h"
#include <stdlib.h>
#include <limits>
#include <string>
#include <algorithm>
#include <type_traits>
#include "nsDebug.h"
//------------------------------------------------------------------------------
static_assert(MOZ_ALIGNOF(Pickle::memberAlignmentType) >= MOZ_ALIGNOF(uint32_t),
"Insufficient alignment");
static const uint32_t kHeaderSegmentCapacity = 64;
static const uint32_t kDefaultSegmentCapacity = 4096;
static const char kBytePaddingMarker = char(0xbf);
namespace {
// We want to copy data to our payload as efficiently as possible.
// memcpy fits the bill for copying, but not all compilers or
// architectures support inlining memcpy from void*, which has unknown
// static alignment. However, we know that all the members of our
// payload will be aligned on memberAlignmentType boundaries. We
// therefore use that knowledge to construct a copier that will copy
// efficiently (via standard C++ assignment mechanisms) if the datatype
// needs that alignment or less, and memcpy otherwise. (The compiler
// may still inline memcpy, of course.)
template <typename T, size_t size, bool hasSufficientAlignment>
struct Copier {
static void Copy(T* dest, const char* iter) { memcpy(dest, iter, sizeof(T)); }
};
// Copying 64-bit quantities happens often enough and can easily be made
// worthwhile on 32-bit platforms, so handle it specially. Only do it
// if 64-bit types aren't sufficiently aligned; the alignment
// requirements for them vary between 32-bit platforms.
#ifndef HAVE_64BIT_BUILD
template <typename T>
struct Copier<T, sizeof(uint64_t), false> {
static void Copy(T* dest, const char* iter) {
# if MOZ_LITTLE_ENDIAN
static const int loIndex = 0, hiIndex = 1;
# else
static const int loIndex = 1, hiIndex = 0;
# endif
static_assert(MOZ_ALIGNOF(uint32_t*) == MOZ_ALIGNOF(void*),
"Pointers have different alignments");
const uint32_t* src = reinterpret_cast<const uint32_t*>(iter);
uint32_t* uint32dest = reinterpret_cast<uint32_t*>(dest);
uint32dest[loIndex] = src[loIndex];
uint32dest[hiIndex] = src[hiIndex];
}
};
#endif
template <typename T, size_t size>
struct Copier<T, size, true> {
static void Copy(T* dest, const char* iter) {
// The pointer ought to be properly aligned.
DCHECK_EQ((((uintptr_t)iter) & (MOZ_ALIGNOF(T) - 1)), 0);
*dest = *reinterpret_cast<const T*>(iter);
}
};
} // anonymous namespace
PickleIterator::PickleIterator(const Pickle& pickle)
: iter_(pickle.buffers_.Iter()) {
iter_.Advance(pickle.buffers_, pickle.header_size_);
}
template <typename T>
void PickleIterator::CopyInto(T* dest) {
static_assert(std::is_trivially_copyable<T>::value,
"Copied type must be a POD type");
Copier<T, sizeof(T),
(MOZ_ALIGNOF(T) <=
sizeof(Pickle::memberAlignmentType))>::Copy(dest, iter_.Data());
}
bool Pickle::IteratorHasRoomFor(const PickleIterator& iter,
uint32_t len) const {
// Make sure we don't get into trouble where AlignInt(len) == 0.
MOZ_RELEASE_ASSERT(len < 64);
return iter.iter_.HasRoomFor(AlignInt(len));
}
bool Pickle::HasBytesAvailable(const PickleIterator* iter, uint32_t len) const {
return iter->iter_.HasBytesAvailable(buffers_, len);
}
void Pickle::UpdateIter(PickleIterator* iter, uint32_t bytes) const {
// Make sure we don't get into trouble where AlignInt(bytes) == 0.
MOZ_RELEASE_ASSERT(bytes < 64);
iter->iter_.Advance(buffers_, AlignInt(bytes));
}
// Payload is sizeof(Pickle::memberAlignmentType) aligned.
Pickle::Pickle(uint32_t header_size, size_t segment_capacity)
: buffers_(AlignInt(header_size),
segment_capacity ? segment_capacity : kHeaderSegmentCapacity,
segment_capacity ? segment_capacity : kDefaultSegmentCapacity),
header_(nullptr),
header_size_(AlignInt(header_size)) {
DCHECK(static_cast<memberAlignmentType>(header_size) >= sizeof(Header));
DCHECK(header_size_ <= kHeaderSegmentCapacity);
header_ = reinterpret_cast<Header*>(buffers_.Start());
header_->payload_size = 0;
}
Pickle::Pickle(uint32_t header_size, const char* data, uint32_t length)
: buffers_(length, AlignCapacity(length), kDefaultSegmentCapacity),
header_(nullptr),
header_size_(AlignInt(header_size)) {
DCHECK(static_cast<memberAlignmentType>(header_size) >= sizeof(Header));
DCHECK(header_size <= kHeaderSegmentCapacity);
MOZ_RELEASE_ASSERT(header_size <= length);
header_ = reinterpret_cast<Header*>(buffers_.Start());
memcpy(header_, data, length);
}
Pickle::Pickle(Pickle&& other)
: buffers_(std::move(other.buffers_)),
header_(other.header_),
header_size_(other.header_size_) {
other.header_ = nullptr;
}
Pickle::~Pickle() {}
Pickle& Pickle::operator=(Pickle&& other) {
BufferList tmp = std::move(other.buffers_);
other.buffers_ = std::move(buffers_);
buffers_ = std::move(tmp);
// std::swap(buffers_, other.buffers_);
std::swap(header_, other.header_);
std::swap(header_size_, other.header_size_);
return *this;
}
void Pickle::CopyFrom(const Pickle& other) {
MOZ_ALWAYS_TRUE(buffers_.CopyFrom(other.buffers_));
MOZ_ASSERT(other.header_ ==
reinterpret_cast<const Header*>(other.buffers_.Start()));
header_ = reinterpret_cast<Header*>(buffers_.Start());
header_size_ = other.header_size_;
}
bool Pickle::ReadBool(PickleIterator* iter, bool* result) const {
int tmp;
if (!ReadScalar(iter, &tmp)) return false;
DCHECK(0 == tmp || 1 == tmp);
*result = tmp ? true : false;
return true;
}
bool Pickle::ReadInt16(PickleIterator* iter, int16_t* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadUInt16(PickleIterator* iter, uint16_t* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadInt(PickleIterator* iter, int* result) const {
return ReadScalar(iter, result);
}
// Always written as a 64-bit value since the size for this type can
// differ between architectures.
bool Pickle::ReadLong(PickleIterator* iter, long* result) const {
int64_t big_result;
if (!ReadScalar(iter, &big_result)) return false;
DCHECK(big_result <= LONG_MAX && big_result >= LONG_MIN);
*result = static_cast<long>(big_result);
return true;
}
// Always written as a 64-bit value since the size for this type can
// differ between architectures.
bool Pickle::ReadULong(PickleIterator* iter, unsigned long* result) const {
uint64_t big_result;
if (!ReadScalar(iter, &big_result)) return false;
DCHECK(big_result <= ULONG_MAX);
*result = static_cast<unsigned long>(big_result);
return true;
}
bool Pickle::ReadLength(PickleIterator* iter, int* result) const {
if (!ReadScalar(iter, result)) return false;
return ((*result) >= 0);
}
bool Pickle::ReadInt32(PickleIterator* iter, int32_t* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadUInt32(PickleIterator* iter, uint32_t* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadInt64(PickleIterator* iter, int64_t* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadUInt64(PickleIterator* iter, uint64_t* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadDouble(PickleIterator* iter, double* result) const {
return ReadScalar(iter, result);
}
// Always written as a 64-bit value since the size for this type can
// differ between architectures.
bool Pickle::ReadIntPtr(PickleIterator* iter, intptr_t* result) const {
DCHECK(iter);
int64_t big_result;
if (!ReadScalar(iter, &big_result)) return false;
DCHECK(big_result <= std::numeric_limits<intptr_t>::max() &&
big_result >= std::numeric_limits<intptr_t>::min());
*result = static_cast<intptr_t>(big_result);
return true;
}
bool Pickle::ReadUnsignedChar(PickleIterator* iter,
unsigned char* result) const {
return ReadScalar(iter, result);
}
bool Pickle::ReadString(PickleIterator* iter, std::string* result) const {
DCHECK(iter);
int len;
if (!ReadLength(iter, &len)) return false;
auto chars = mozilla::MakeUnique<char[]>(len);
if (!ReadBytesInto(iter, chars.get(), len)) {
return false;
}
result->assign(chars.get(), len);
return true;
}
bool Pickle::ReadWString(PickleIterator* iter, std::wstring* result) const {
DCHECK(iter);
int len;
if (!ReadLength(iter, &len)) return false;
// Avoid integer multiplication overflow.
if (len > INT_MAX / static_cast<int>(sizeof(wchar_t))) return false;
auto chars = mozilla::MakeUnique<wchar_t[]>(len);
if (!ReadBytesInto(iter, chars.get(), len * sizeof(wchar_t))) {
return false;
}
result->assign(chars.get(), len);
return true;
}
bool Pickle::ReadBytesInto(PickleIterator* iter, void* data,
uint32_t length) const {
if (AlignInt(length) < length) {
return false;
}
if (!buffers_.ReadBytes(iter->iter_, reinterpret_cast<char*>(data), length)) {
return false;
}
return iter->iter_.AdvanceAcrossSegments(buffers_, AlignInt(length) - length);
}
bool Pickle::IgnoreBytes(PickleIterator* iter, uint32_t length) const {
if (AlignInt(length) < length) {
return false;
}
return iter->iter_.AdvanceAcrossSegments(buffers_, AlignInt(length));
}
#ifdef MOZ_PICKLE_SENTINEL_CHECKING
MOZ_NEVER_INLINE
bool Pickle::ReadSentinel(PickleIterator* iter, uint32_t sentinel) const {
uint32_t found;
if (!ReadScalar(iter, &found)) {
return false;
}
return found == sentinel;
}
bool Pickle::IgnoreSentinel(PickleIterator* iter) const {
uint32_t found;
return ReadUInt32(iter, &found);
}
bool Pickle::WriteSentinel(uint32_t sentinel) { return WriteUInt32(sentinel); }
#endif
void Pickle::EndRead(PickleIterator& iter, uint32_t ipcMsgType) const {
// FIXME: Deal with the footer somehow...
// DCHECK(iter.iter_.Done());
}
void Pickle::Truncate(PickleIterator* iter) {
size_t dropped = buffers_.Truncate(iter->iter_);
header_->payload_size -= dropped;
}
static const char kBytePaddingData[4] = {
kBytePaddingMarker,
kBytePaddingMarker,
kBytePaddingMarker,
kBytePaddingMarker,
};
static void WritePadding(Pickle::BufferList& buffers, uint32_t padding) {
MOZ_RELEASE_ASSERT(padding <= 4);
if (padding) {
MOZ_ALWAYS_TRUE(buffers.WriteBytes(kBytePaddingData, padding));
}
}
void Pickle::BeginWrite(uint32_t length) {
// write at an alignment-aligned offset from the beginning of the header
uint32_t offset = AlignInt(header_->payload_size);
uint32_t padding = (header_size_ + offset) % sizeof(memberAlignmentType);
uint32_t new_size = offset + padding + AlignInt(length);
MOZ_RELEASE_ASSERT(new_size >= header_->payload_size);
DCHECK(intptr_t(header_) % sizeof(memberAlignmentType) == 0);
#ifdef HAVE_64BIT_BUILD
DCHECK_LE(length, std::numeric_limits<uint32_t>::max());
#endif
WritePadding(buffers_, padding);
DCHECK((header_size_ + header_->payload_size + padding) %
sizeof(memberAlignmentType) ==
0);
header_->payload_size = new_size;
}
void Pickle::EndWrite(uint32_t length) {
uint32_t padding = AlignInt(length) - length;
WritePadding(buffers_, padding);
}
bool Pickle::WriteBool(bool value) { return WriteInt(value ? 1 : 0); }
bool Pickle::WriteInt16(int16_t value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteUInt16(uint16_t value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteInt(int value) { return WriteBytes(&value, sizeof(value)); }
bool Pickle::WriteLong(long value) {
// Always written as a 64-bit value since the size for this type can
// differ between architectures.
return WriteInt64(int64_t(value));
}
bool Pickle::WriteULong(unsigned long value) {
// Always written as a 64-bit value since the size for this type can
// differ between architectures.
return WriteUInt64(uint64_t(value));
}
bool Pickle::WriteInt32(int32_t value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteUInt32(uint32_t value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteInt64(int64_t value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteUInt64(uint64_t value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteDouble(double value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteIntPtr(intptr_t value) {
// Always written as a 64-bit value since the size for this type can
// differ between architectures.
return WriteInt64(int64_t(value));
}
bool Pickle::WriteUnsignedChar(unsigned char value) {
return WriteBytes(&value, sizeof(value));
}
bool Pickle::WriteBytesZeroCopy(void* data, uint32_t data_len,
uint32_t capacity) {
BeginWrite(data_len);
uint32_t new_capacity = AlignInt(capacity);
#ifndef MOZ_MEMORY
if (new_capacity > capacity) {
// If the buffer we were given is not large enough to contain padding
// after the data, reallocate it to make it so. When using jemalloc,
// we're guaranteed the buffer size is going to be at least 4-bytes
// aligned, so we skip realloc altogether. Even with other allocators,
// the realloc is likely not necessary, but we don't take chances.
// At least with ASan, it does matter to realloc to inform ASan we're
// going to use more data from the buffer (and let it actually realloc
// if it needs to).
data = realloc(data, new_capacity);
}
#endif
// Shouldn't fail, because we're using InfallibleAllocPolicy.
MOZ_ALWAYS_TRUE(buffers_.WriteBytesZeroCopy(reinterpret_cast<char*>(data),
data_len, new_capacity));
EndWrite(data_len);
return true;
}
bool Pickle::WriteBytes(const void* data, uint32_t data_len) {
BeginWrite(data_len);
MOZ_ALWAYS_TRUE(
buffers_.WriteBytes(reinterpret_cast<const char*>(data), data_len));
EndWrite(data_len);
return true;
}
bool Pickle::WriteString(const std::string& value) {
if (!WriteInt(static_cast<int>(value.size()))) return false;
return WriteBytes(value.data(), static_cast<int>(value.size()));
}
bool Pickle::WriteWString(const std::wstring& value) {
if (!WriteInt(static_cast<int>(value.size()))) return false;
return WriteBytes(value.data(),
static_cast<int>(value.size() * sizeof(wchar_t)));
}
bool Pickle::WriteData(const char* data, uint32_t length) {
return WriteInt(length) && WriteBytes(data, length);
}
void Pickle::InputBytes(const char* data, uint32_t length) {
MOZ_ALWAYS_TRUE(buffers_.WriteBytes(data, length));
}
int32_t* Pickle::GetInt32PtrForTest(uint32_t offset) {
size_t pos = buffers_.Size() - offset;
BufferList::IterImpl iter(buffers_);
MOZ_RELEASE_ASSERT(iter.AdvanceAcrossSegments(buffers_, pos));
return reinterpret_cast<int32_t*>(iter.Data());
}
// static
uint32_t Pickle::MessageSize(uint32_t header_size, const char* start,
const char* end) {
DCHECK(header_size == AlignInt(header_size));
DCHECK(header_size <=
static_cast<memberAlignmentType>(kHeaderSegmentCapacity));
if (end < start) return 0;
size_t length = static_cast<size_t>(end - start);
if (length < sizeof(Header)) return 0;
const Header* hdr = reinterpret_cast<const Header*>(start);
if (length < header_size) return 0;
mozilla::CheckedInt<uint32_t> sum(header_size);
sum += hdr->payload_size;
if (!sum.isValid()) return 0;
return sum.value();
}